Electric power conversion device

An electric power conversion device comprising at least one IGBT and means for driving the IGBT, wherein the electric power conversion device includes:

• an IGBT including an emitter having flowing therethrough a principal current, and a sense emitter having flowing therethrough a sense current proportional to the principal current;
• temperature measurement means disposed on the same semiconductor substrate as the IGBT;
• and
• principal current estimation means for receiving an output of the temperature measurement means and a current flowing through the sense emitter, and thereby estimating the principal current, and
• the principal current estimation means includes:
• current-voltage conversion means for converting the sense current to a voltage;
• pulse conversion means for performing conversion to a pulse width proportional to a voltage outputted by the current-voltage conversion means;
• count means for counting the pulse width;
• memory means for storing a relationship among a semiconductor substrate temperature of the IGBT, the principal current and the sense current;
• calculation means for receiving the relationship information, stored in the memory means, among the semiconductor substrate temperature, the principal current and the sense current, the information on sense current outputted by the count means, and the information on temperature of the IGBT, and thereby calculating the principal current.

An electric power conversion device comprising at least one IGBT and means for driving the IGBT, wherein:

• the IGBT has included on one principal surface of a semiconductor substrate thereof a collector electrode, and on another surface of the semiconductor substrate an emitter having flowing therethrough a principal current, a sense emitter having flowing therethrough a sense current proportional to the principal current, and temperature measurement means;
• the temperature measurement means is a diode disposed via an insulating layer;
• the IGBT includes principal current estimation means for receiving an output of the temperature measurement means and a current flowing through the sense emitter and thereby estimating the principal current;
• and
• the principal current estimation means includes A/D conversion means for converting a voltage outputted by the temperature measurement means from analog to digital form.